American Glaucoma Society Position Paper: Microinvasive Glaucoma Surgery

Outcomes and baseline predictors of failure in primary standalone Xen45 gel stent vs trabeculectomy for glaucoma

PURPOSE

To compare safety, effectiveness and baseline predictors of failure in standalone primary Xen45 gel stent (Xen) vs trabeculectomy (Trab) in glaucoma.

DESIGN

Retrospective study SUBJECTS: Subjects that underwent primary Xen or Trab augmented by mitomycin-C with at least 12 months follow-up.

METHODS

Multinational observational study of eyes in the Fight Glaucoma Blindness international registry MAIN OUTCOME MEASURES: The primary outcome was success at 12 months defined by IOP reduction ≥ 20% from baseline and ≤ threshold IOPs of 15mmHg, 18mmHg and 21mmHg with (qualified) or without (complete) medications and without secondary glaucoma surgery. Multivariable mixed effects cox regression models were used to identify risk factors for failure in each cohort.

RESULTS

701 eyes (Xen, 308; Trab, 393) of 596 subjects were included with baseline IOP being significantly higher (22.4 vs 19.9 mmHg, p < 0.001) and baseline medications significantly lower in the Xen vs the Trab group (2.9 vs 3.4, p <0.001). Baseline visual field (VF) mean deviation (MD) was less severe in the Xen group (-9.47 vs -13.04 dB, p < 0.001). The proportion of complete surgical success was significantly lower in the Xen vs Trab group across the three upper IOP limits at 12 months; 32% vs 52% at 15mmHg, 37% vs 54% at 18mmHg, and 39% vs 55% at 21mmHg (p < 0.001). The incidence of post-operative numerical and symptomatic hypotony was lower in the Xen vs Trab group. In the Xen cohort, a higher failure rate was associated with Asian ethnicity (HR, 1.97; 95% CI, 1.03-3.79) and use of oral acetazolamide at baseline (HR, 1.74; 1.13-2.70), while a lower failure rate was associated with diagnosis of ocular hypertension/open angle glaucoma suspect (HR, 0.52; 0.28-0.94) and secondary open angle glaucoma (HR, 0.45; 0.25-0.8). Exposure to prostaglandin analogue was associated with greater failure in the Trab group (HR, 2.66; 1.18-6.01).

CONCLUSIONS

There was significantly greater complete success at 12 months across all complete success definitions for Trab compared to Xen, while the rate of post-operative hypotony was significantly lower in Xen group. Asian ethnicity and use of oral acetazolamide at baseline were associated with greater failure in Xen, while exposure to prostaglandin analogue was associated with greater failure in Trab patients. Such baseline predictors of success and failure may help guide patient selection for subconjunctival minimally invasive glaucoma surgery in patients undergoing surgical intervention.

Minimally invasive bleb surgery versus minimally invasive glaucoma surgery: a 12-month retrospective study

This study aimed to compare the IOP-lowering effectiveness and safety of standalone Preserflo MicroShunt and iStent 1st generation implantation combined with phacoemulsification in Caucasian patients with a 12-month follow-up period. This retrospective study analyzed the medical histories of patients undergoing antiglaucoma surgery at the Department of Ophthalmology, Medical University of Bialystok, between January 2019 and January 2022. The main outcome measures were success rates (complete: proportion of eyes with IOP < 18 mmHg (criterion A) and < 15 mmHg (criterion B) or 20% reduction in IOP without any glaucoma medication; qualified: proportion of eyes achieving IOPs < 18 mmHg and < 15 mmHg or 20% reduction in IOP from baseline with or without medications), mean reduction (%) in IOP, medication burden, number of complications and additional interventions. In both groups, a significant decrease in IOP and medication burden were observed at 6 and 12 months when compared with baseline. At 12 months, qualified surgical success in criterion A was recorded in 67.4% and 85.7% of patients in the Preserfo and iStent groups, respectively (p = 0.045). Complete surgical success in criterion B at 12 months accounted to 61.4% of patients from Prserflo group and 32.7% patients in iStent group (p = 0.04). Surgical failure at 12 months was documented in 30.2% and 6.3% of patients, respectively (p = 0.003). There was a significant difference between groups in %IOP reduction after 12 months. Greater reduction was observed in Preserflo group, MD = - 8.41 CI95 [- 15.88; - 0.95], p = 0.028, (- 33.49% ± 21.59 vs - 25.07% ± 14.15 in iStent group). Both procedures effectively reduced IOP and postoperative use of antiglaucoma medications in glaucoma patients.

Quantification of Postoperative Inflammation in Laser and Surgical Procedures for Glaucoma with Laser Flare Photometry: A Review of the Literature

PURPOSE

To review the application of laser flare photometry (LFP) in the objective quantification of aqueous flare (anterior chamber inflammation) post laser and surgical procedures for glaucoma.

METHODS

A search was undertaken using the following: PubMed (all years), the Web of Science (all years), Ovid MEDLINE (R) (1980 to 30 March 2023), Ovid MEDLINE (R) Daily Update 30 March 2023, MEDLINE and MEDLINE non-indexed items, Embase (1980-2021, week 52), Ovid MEDLINE (R) and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1980 to 30 March 2023), CENTRAL (including Cochrane Eyes and Vision Trials Register), metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (www.who.int/ictrp/search/en). Search terms included "aqueous flare," "anterior chamber inflammation," "tyndallometry," "laser flare photometry" combined with "laser," "iridotomy," "trabeculoplasty," "cataract surgery," "phacoemulsification," "glaucoma surgery," "minimally invasive glaucoma surgery," "trabeculectomy," "aqueous shunt," "glaucoma drainage" and "cyclophotocoagulation."

RESULTS

The majority of studies utilizing laser flare photometry in grading flare have been post laser trabeculoplasty. The degree of flare produced varies according to the type of glaucoma laser or surgery performed, with filtration procedures and glaucoma drainage devices having marked and prolonged detectable levels. Aqueous flare in cyclodestructive procedures positively correlated with intraocular pressure (IOP) reduction.

CONCLUSION

In comparison to clinician grading, laser flare photometry provides a more objective measure of post-surgical inflammation in eyes that have undergone laser and surgery for glaucoma. Further research is warranted into how this instrument can be utilized to identify eyes at high risk of failure and other adverse outcomes after glaucoma surgery.

The Evolution and Current Landscape of Minimally Invasive Glaucoma Surgeries: A Review

This review examines the evolution, current status, and future potential of minimally invasive glaucoma surgeries (MIGS), a significant advancement in the treatment of glaucoma, a leading cause of irreversible blindness. MIGS offer a less invasive alternative to traditional glaucoma surgeries, primarily aimed at reducing intraocular pressure, minimizing tissue trauma, and providing a safer profile. With the emergence of devices such as the Trabectome, iStent, and others, MIGS have expanded the surgical toolkit, allowing personalized, patient-centered care. Despite their advantages, MIGS face challenges such as efficacy in severe cases, long-term data, and accessibility. Ongoing research and technological innovations continue to refine their capabilities and applications, promising to further transform glaucoma management and patient outcomes. This paper provides an in-depth analysis of MIGS, reflecting on their impact and contemplating future directions in this dynamically evolving field.

[Review by the French Glaucoma Society on the roles of new surgical techniques in glaucoma]

The surgical management of glaucoma has been enriched in recent years by the arrival of new surgical techniques as a group known as MIGS (minimally invasive glaucoma surgery). The objective of these new techniques is to reduce intraocular pressure (IOP) while limiting the risk of complications of conventional filtering surgery and allowing faster visual recovery. MIGS can be classified into three main categories depending on the route used to promote the outflow of aqueous humor: the trabecular route, the suprachoroidal route and the subconjunctival route. MIGS using the subconjunctival route are also called minimally invasive bleb surgery (MIBS). These new techniques do not replace conventional filtering surgery, which remains the gold standard technique, but now offer new alternatives for the surgical management of glaucoma patients in combination with cataract surgery or as stand-alone procedures.

Trends in the National Ophthalmological Healthcare Focusing on Cataract, Retina, and Glaucoma Over 15 Years in Japan

To assess the trends in ophthalmic healthcare, especially those of cataract, vitreo-retinal diseases, and glaucoma, the national data from the Japanese Ministry of Health, Labour and Welfare, which recorded medical practices for 126.1 million citizens, were studied for 15 years. The volume and expenses of cataract surgeries increased during this period; however, non-surgical expenses decreased. As a result, the total national cataract healthcare expenses decreased over the 15-year period. The volume of vitrectomies increased from 2007 to 2013. After introduction of anti-vascular endothelial growth factor (VEGF) injections, the number of injections increased 8.4 times from 2010 to 2021, while the volume of vitrectomy and retinal photocoagulation declined after 2019 and 2017, respectively. Minimally invasive glaucoma and long-tube shunt surgeries began to increase in 2015 and 2014, respectively. This trend contrasts with the decrease in trabeculectomies after 2019. The coronavirus disease-19 pandemic caused a 30.9% decrease in ophthalmological surgery expenses in 2020. The decreases in volume and expense were greater for cataract surgeries than for other surgeries. The pandemic had a stronger impact on ophthalmological healthcare than that on general medical healthcare. Advancements in technology and methodology have led to cost savings in national cataract healthcare, vitrectomy, and retinal photocoagulation while caused increase in the volume and expenditure of glaucoma surgeries and anti-VEGF injections over a span of 15 years in Japan.

Disparities in Glaucoma Surgery: A Review of Current Evidence and Future Directions for Improvement

There is a need to understand existing disparities in glaucoma surgery and to create strategies to eliminate these disparities. Disparities can exist in several aspects of glaucoma surgical management, including patient selection and timing of surgery, type of surgery performed, intra-operative and postoperative surgical complications, follow-up surgical care, and long-term surgical outcomes. Additionally, multiple types of disparities can exist within each of these realms, including disparities by race and ethnicity, age, gender, insurance type, people with disabilities, and other social, economic, and demographic factors. Disparities in glaucoma surgery have been examined in large scale datasets, retrospective clinical studies, and clinical trials, and several studies have identified likely racial and ethnic disparities in glaucoma surgical incidence and outcomes. We present existing literature on disparities in glaucoma surgery, analyze the advantages and limitations of various study designs for the investigation of these disparities, and propose directions for future research and interventions to identify and eliminate disparities in surgical glaucoma care.

[Minimally invasive glaucoma surgery-Comparison of angle based procedures]

Surgical procedures are playing an increasing role in the care of patients with glaucoma. Within the last decade, new surgical procedures have been established, which are summarized under the term minimally invasive glaucoma surgery (MIGS). A wide variety of different procedures are aimed at the structures in the angle of the anterior chamber, such as the trabecular meshwork and Schlemm's canal, to improve the physiological outflow or to improve the alternative uveoscleral outflow. The implementation of the treatment goal differs in the individual procedures, as does the maximum pressure reduction that can be achieved. Compared to trabeculectomy with the use of cytostatic agents, the achievable pressure reduction is usually significantly lower. In contrast, the significantly lower intraoperative and postoperative complication rates are emphasized as an advantage of these procedures. With increasing clinical experience and the growth of sufficient data on these new surgical procedures, a well-founded classification in the treatment algorithm of glaucoma surgery becomes easier; nevertheless, due to the small differences with respect to efficacy and safety profile, the final decision for an individual procedure often remains dependent on the surgeon's personal preferences.

The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm

PURPOSE OF REVIEW

To highlight progress in glaucoma therapy challenging the traditional medication-first approach and present evidence supporting early standalone surgery in the era of micro-invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Medical therapy is limited by well documented poor adherence that compromises the quality of intraocular pressure reduction. Results from modern clinical trials demonstrate advantages of selective laser trabeculoplasty and MIGS procedures in terms of both IOP control and progression risk.

SUMMARY

The MIGS options for pseudophakic or precataractous patients are limited by regulatory rules that require the performance of some procedures only at the time of cataract surgery. These include the iStent/iStent Inject and the Hydrus implants. Nonbleb-forming procedures currently available for standalone use in eyes with mild-moderate primary open-angle glaucoma include gonioscopy-assisted transluminal trabeculotomy (which lowers IOP by 28-61% and medication use by 38-73% in various studies), trabecular ablation with the Trabectome (23-39% and 21-43%, respectively), excisional goniotomy with the Kahook Dual Blade (15-36% and 15-40%, respectively), ab interno canaloplasty (35% and 57%, respectively), and combined canaloplasty and trabeculotomy using the OMNI system (39-40% and 64-73%, respectively). For patients who would benefit from early standalone surgery, these procedures offer meaningful reductions in both IOP and medication burden.

The PreserFlo MicroShunt in the Context of Minimally Invasive Glaucoma Surgery: A Narrative Review

Recently, the quest for novel glaucoma surgical techniques and devices has been underway. Trabeculectomy remains the gold standard, but it requires the implantation of glaucoma drainage devices and frequent follow-ups, and it also carries a high risk of serious complications. The need for less invasive and safer procedures has led to the development of minimally invasive glaucoma surgery (MIGS), particularly for patients with mild-to-moderate disease. Among them, minimally invasive bleb surgery seems to be effective in classical glaucoma surgery, while maintaining MIGS benefits. The relatively new PreserFlo® MicroShunt (Santen, Osaka, Japan) is registered in Europe. It was released in 2019 for the treatment of patients with early-to-advanced open-angle glaucoma, where intraocular pressure (IOP) remains uncontrolled while on maximum tolerated medication and/or where glaucoma progression warrants surgery. This review focuses on the place of the PreserFlo MicroShunt, characterized by ab externo implantation, among MIGS procedures, discussing its advantages and disadvantages. The mechanisms of action, technical aspects, efficacy, and safety issues are summarized. The surgical technique, its efficacy, and safety profile are described, and directions for future studies are indicated. The PreserFlo MicroShunt ensures a high safety profile, minimal anatomical disruption, meaningful IOP-lowering effect, and ease of use for patients and physicians.

Effectiveness and cost-effectiveness of MicroShunt implantation versus standard trabeculectomy for open-angle glaucoma (a SIGHT study): study protocol of a multicentre randomised controlled trial

BACKGROUND

Trabeculectomy is the "gold standard" initial surgical procedure for open-angle glaucoma worldwide. During the last decade, the introduction of less invasive procedures, including new bleb-forming surgery such as the MicroShunt, has altered the approach of glaucoma management. At present, there is insufficient evidence comparing the effectiveness between these procedures nor versus trabeculectomy. Furthermore, there is no data available on patient impact and cost-effectiveness. This study aims to address this gap in evidence and establish whether MicroShunt implantation is non-inferior compared to trabeculectomy with regard to effectiveness and whether it is cost-effective.

METHODS

A multicentre, non-inferiority, randomised controlled trial (RCT) studying open-angle glaucoma with an indication for surgery will be conducted. Patients with previous ocular surgery except for phacoemulsification are excluded, as are patients with ocular comorbidity compromising the visual field or requiring a combined procedure. After informed consent is obtained, patients will be randomly allocated to the intervention, a PRESERFLO™ MicroShunt implantation, or the control group, trabeculectomy, using block randomisation (blocks of 2, 4 or 6 patients). In total, 124 patients will be randomised in a 1:1 ratio, stratified by centre. The primary endpoint will be intraocular pressure (IOP) one year after surgery. Secondary outcomes include IOP-lowering medication use, treatment failure, visual acuity, visual field progression, additional interventions, adverse events, patient-reported outcome measures (PROMs), and cost-effectiveness. Study outcomes will be measured up to 12 months postoperatively.

DISCUSSION

This study protocol describes the design of a multicentre non-inferiority randomised controlled trial. To this date, cost-effectiveness studies evaluating the MicroShunt have not been undertaken. This multicentre RCT will provide more insight into whether MicroShunt implantation is non-inferior compared to standard trabeculectomy regarding postoperative IOP and whether MicroShunt implantation is cost-effective.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT03931564 , Registered 30 April 2019.

Devices and Treatments to Address Low Adherence in Glaucoma Patients: A Narrative Review

Poor adherence to topical glaucoma medications has been linked to worse visual field outcomes in glaucoma patients. Therefore, identifying and overcoming the adherence barriers are expected to slow down the progression of disease. The most common barriers to adherence, in addition to the lack of knowledge, include forgetfulness, side effects of medications, difficulties with drop instillation and low self-efficacy. Symptoms and signs of ocular surface disease, which importantly reduce patients' quality of life, are decreased by using preservative-free topical medications. Sustained drug delivery systems using different vehicles seem promising for relieving the burden of drop administration. Currently, only the bimatoprost sustained-release intracameral implant is available for clinical use and single administration. In the era of digitalization, smart drug delivery-connected devices may aid adherence and, by sharing data with care providers, improve monitoring and adjusting treatment. Selective laser trabeculoplasty as first-line treatment delays the need for drops, whereas minimally invasive glaucoma procedures with and without devices combined with cataract surgery increase the likelihood of patients with early-to-moderate glaucoma to remain drop free or reduce the number of drops needed to control intraocular pressure. The aim of this narrative review is to present and discuss devices and treatments that may improve adherence by reducing the need for drops and side effects of medications and aiding in glaucoma monitoring. For the future, there is a need for studies focusing on clinically important outcomes, quality of life and the cost of intervention with longer post-interventional follow up.

Preserflo Microshunt Surgery for Ocular Hypertension following Intravitreal Fluocinolone Acetonide Implant Removal: A Case Report

Diabetic macular edema (DME) is now a well-known condition for which a number of treatments have been shown to be effective. Intraocular corticosteroids are part of this therapeutic arsenal but are sometimes responsible for ocular hypertension. We describe here the case of a 60-year-old man with a history of bilateral DME who received an intravitreal injection of 190 µg fluocinolone acetonide (FAc) (ILUVIEN^®, Alimera Sciences, Alpharetta, GA, USA) who presented a persistent ocular hypertension in one eye despite FAc removal by pars plana vitrectomy and was successfully managed by Preserflo^® microshunt surgery.

Gonioscopy-assisted transluminal trabeculotomy in neovascular glaucoma: Salvaging the conventional outflow pathway

Purpose

To report a case of acute neovascular glaucoma with partial synechial angle closure secondary to central retinal vein occlusion that underwent gonioscopy-assisted transluminal trabeculotomy as well as near-monthly anti-vascular endothelial growth factor (VEGF) injections and panretinal photocoagulation (PRP) treatments.

Observations

Nine months after GATT, the patient had achieved intraocular pressure control on no medications. However, she was lost to follow up for 4 months and received no anti-VEGF or PRP during that time; she re-presented with acute NVG and complete synechial closure, and ultimately underwent aqueous shunt implantation.

Conclusions and Importance

To our knowledge, this is the first reported attempt of an ab interno angle surgery to successfully restore aqueous outflow through the conventional outflow pathway in an eye with acute NVG and partial synechial angle closure. We posit that this can be an effective approach to achieve IOP control in NVG with at least partially open angles, as long as sufficient anti-neovascular treatments are administered until the underlying neovascular drive achieves quiescence.

Updates on the Diagnosis and Management of Glaucoma

Glaucoma is the leading cause of blindness throughout the world (after cataracts); therefore, general physicians should be familiar with the diagnosis and management of affected patients. Glaucomas are usually categorized by the anatomy of the anterior chamber angle (open vs narrow/closed), rapidity of onset (acute vs chronic), and major etiology (primary vs secondary). Most glaucomas are primary (ie, without a contributing comorbidity); however, several coexisting ophthalmic conditions may serve as the underlying etiologies of secondary glaucomas. Chronic glaucoma occurs most commonly; thus, regular eye examinations should be performed in at-risk patients to prevent the insidious loss of vision that can develop before diagnosis. Glaucoma damages the optic nerve and retinal nerve fiber layer, leading to peripheral and central visual field defects. Elevated intraocular pressure (IOP), a crucial determinant of disease progression, remains the only modifiable risk factor; thus, all current treatments (medications, lasers, and operations) aim to reduce the IOP. Pharmacotherapy is the usual first-line therapy, but noncompliance, undesirable adverse effects, and cost limit effectiveness. Laser and surgical treatments may lower IOP significantly over long periods and may be more cost effective than pharmacotherapy, but they are plagued by greater procedural risks and frequent treatment failures. Traditional incisional procedures have recently been replaced by several novel, minimally invasive glaucoma surgeries with improved safety profiles and only minimal decreases in efficacy. Minimally invasive glaucoma surgeries have dramatically transformed the surgical management of glaucoma; nevertheless, large, randomized trials are required to assess their long-term efficacy.

Canaloplasty and trabeculotomy with the OMNI® surgical system in OAG with prior trabecular microbypass stenting

Purpose

Evaluate effectiveness and safety outcomes for patients treated with canaloplasty and trabeculotomy previously treated with a trabecular microbypass stent (TBS).

Methods

Retrospective, multicenter, IRB approved study. Patients treated with TBS (iStent/iStent inject, Glaukos) and subsequently with OMNI surgical system (OSS) (Sight Sciences). From 5 practices in 5 US states. Open-angle glaucoma (OAG), minimum 3 months follow-up after OSS surgery, Pre-OSS IOP ≥ 17 mmHg on ≥ 1 medication. No glaucoma procedures between TBS and OSS. Endpoints: proportion with ≥ 20% reduction in IOP, IOP between 6 and 18 mmHg, mean IOP, change in IOP, mean number of medications. Adverse events and secondary surgical interventions (SSI). Mann–Whitney rank sum test compared pre-OSS IOP and medications with follow-up.

Results

Twenty seven patients. Average age (SD) 72.2 (10.8), 22/27 primary OAG (82%), mean MD − 6.2 (7.0) dB. Mean IOP before OSS 22.3 (4.3) mmHg on 2.2 (1.3) medications. At last follow-up (mean 11 months) IOP was 17.2 mmHg on 1.8 medications, − 5.1 mmHg (− 23%, p < .001), − 0.4 meds (− 18%, p = .193); ≥ 20% IOP reduction (41%), IOP ≤ 18 (56%). Adverse events were non-serious. Hyphema > 1 mm (3, 11%), BCVA decrease (4, 15%), IOP spike (2, 7%). SSI (4, 15%) had higher pre-OSS IOP (23.4 mmHg) and worse MD (− 9.6 dB).

Conclusion

Patients uncontrolled by medication and a prior TBS would once have been candidates for trabeculectomy and tube shunts. OSS offered a minimally invasive option that provided IOP control and avoidance of traditional surgery for the majority over follow-up averaging 11 months and up to 42 months.

Size Matters: Ab Interno Canaloplasty Revision with Suture Trabeculotomy

Aim

To report the efficacy of the revision of failed ab interno canaloplasty with micro-invasive suture trabeculotomy (MIST) over a follow-up period of 24 months.

Materials and methods

A retrospective analysis was performed on 23 eyes with open-angle glaucoma (OAG), on whom an ab interno canaloplasty revision with MIST was performed for glaucoma progression. The primary outcome was the proportion of eyes with a significant intraocular pressure (IOP) reduction at 12 months post trabeculotomy, defined as an IOP ≤ 18 mm Hg or ≥20% reduction in IOP without any secondary intervention (SI), and with the same or fewer number of glaucoma medications (NGM). All parameters, including best corrected visual acuity (BCVA), IOP, NGM, and SI, were evaluated at 1, 6, 12, 18, and 24 months.

Results

At 12 months, eight out of 23 eyes (36.4%) achieved complete success, maintained in six eyes (27.3%) at 24 months. A significantly lower mean IOP was recorded at all visits [14.3 ± 4.0 mm Hg at 24 months vs 23.1 ± 6.8 mm Hg at baseline (BL)] with a percent IOP change of up to 27.3% at 24 months postoperatively. NGM and BCVA did not significantly decrease from BL. A total of 11 eyes (47.8%) needed an SI throughout the follow-up period.

Conclusion

Ab interno trabeculotomy in patients with failed canaloplasty was not shown to be effective in providing a satisfactory control of IOP in OAG patients, possibly due to the small suture gauge used in the initial canaloplasty.

Clinical significance

Further research is needed to optimize the surgical outcome.

How to cite this article

Seif R, Jalbout NDE, Sadaka A, et al. Size Matters: Ab Interno Canaloplasty Revision with Suture Trabeculotomy. J Curr Glaucoma Pract 2022;16(3):152-157.

Intra-Ocular Pressure Response to Dexamethasone Implant Injections in Patients with a History of Filtering Surgery: The TRABEX Study

Patients with both macular edemas, of various etiologies such as diabetes and glaucoma, may suffer serious loss of vision if either disease goes untreated. Where no effective alternative therapies are available, dexamethasone implant (DEX-I) injections may be the only choice of treatment, despite the risk of a possible increase in intraocular pressure (IOP) when using steroids. Although many studies have reported on IOP evolution in eyes treated with DEX-I, little is known specifically about eyes with a history of filtering surgery. The aim of this observational series was to evaluate the IOP response following DEX-I injection in eyes presenting conventional filtering surgeries or microinvasive glaucoma surgeries (MIGS). Twenty-five eyes were included in this study. A total of 64% of the eyes did not experience OHT during follow-up. Additional IOP-lowering therapy was needed for 32% of eyes, and 20% of eyes (all showing bleb fibrosis) required further filtering surgery: 50% of eyes in the MIGS group and 10.5% of eyes in the conventional filtering surgery group. A significant positive correlation was found between IOP at baseline and the maximum IOP throughout follow-ups after DEX-I (r = 0.45, p = 0.02). In conclusion, if DEX-I is used when there are no alternative therapies for treating macular edema, IOP in eyes with a history of filtering surgery is generally manageable. Those eyes which previously underwent conventional therapy with effective blebs obtained better IOP control after DEX-I injections and mostly did not require any additional IOP-lowering therapy or surgery.

Usage Patterns of Minimally Invasive Glaucoma Surgery (MIGS) Differ by Glaucoma Type: IRIS Registry Analysis 2013-2018

PURPOSE

To examine patterns of standard (trabeculectomy or glaucoma drainage devices, GDDs) vs novel (minimally invasive glaucoma surgery, MIGS) surgical techniques in the US.

METHODS

We used the American Academy of Ophthalmology (AAO) IRIS® Registry (Intelligent Research in Sight) queried between 2013 and 2018 (inclusive) to calculate the cumulative proportion of stand-alone, concurrent (same day) or sequential (subsequent day) glaucoma surgical techniques performed in each glaucoma diagnosis type. Secondary analyses of adjusted proportions of concurrent and sequential surgeries stratified by glaucoma diagnosis were also performed.

RESULTS

Of 203,146 eyes receiving glaucoma surgeries, open angle glaucoma (OAG) was most likely to undergo all types of intervention. The iStent was the most commonly performed MIGS, primarily for those with normal tension glaucoma (NTG) or OAG (p < .001). Conversely, GDD was the most commonly performed procedure in secondary glaucoma or other (specified) glaucoma (p < .001). ECP and iStent were the most common concurrent procedures performed; most often for OAG and NTG (p < .001). After an initial standard surgery, most eyes underwent recurrent standard interventions (90.3%). ECP was the most common MIGS performed after an initial standard surgery; particularly in primary angle-closure (PACG) and secondary glaucoma eyes (p < .001).

CONCLUSION

Glaucoma type may influence the choice of glaucoma procedures and the decision to perform concurrent as well sequential surgical procedures. Given the poorly understood long term safety and effectiveness of MIGS, and with substantially increasing use of MIGS procedures in recent years, future studies comparing their safety and effectiveness vs standard interventions, for a variety of glaucoma types, is needed.

Trends and Usage Patterns of Minimally Invasive Glaucoma Surgery in the United States: IRIS® Registry Analysis 2013-2018

PURPOSE

Understanding trends and patterns in the use of minimally invasive glaucoma surgery (MIGS) and patient profiles undergoing each procedure is important given their relative expense and unknown long-term safety and effectiveness.

DESIGN

Retrospective analysis.

PARTICIPANTS

Minimally invasive glaucoma surgeries and standard glaucoma surgeries recorded in the American Academy of Ophthalmology Intelligent Research in Sight (IRIS®) Registry.

METHODS

We used the data from IRIS Registry between 2013 and 2018 (inclusive) to measure the annual number of MIGS and standard surgical techniques (trabeculectomy or glaucoma drainage device [GDD] placement) performed in the United States, stratified by demographic characteristics. Secondary analyses of concurrent surgeries and of subsequent surgeries for MIGS and standard surgical technique also were conducted.

MAIN OUTCOME MEASURES

Trends and sociodemographic characteristics of MIGS use in the United States.

RESULTS

Two hundred three thousand three hundred thirty-two eyes and 232 537 unique procedures had associated, documented International Statistical Classification of Diseases and Related Health Problems (ICD), Ninth or Tenth Revision, codes for glaucoma and were included in final analyses. Among eyes with documented glaucoma diagnoses, a substantial increase in annual MIGS procedures occurred over the study period (from 7586 in 2013 to 39 677) and a smaller decrease in standard glaucoma procedures (from 16 215 to 13 701). The proportion of iStent procedures almost tripled during the study period (from 14% to 40%), and by 2017 accounted for almost half (43.7%) of all glaucoma surgeries in the United States. Twenty-one thousand twenty-five of all eyes (10.3%) underwent multiple procedures: 7638 (36.3%) on the same day and 13 387 (63.7%) on subsequent days. Endocyclophotocoagulation and iStent placement were the most common concurrent procedures (55.4% of all concurrent procedures). Trabeculectomy and GDD placement were most commonly followed by another standard glaucoma surgery, but when followed by sequential MIGS, endocyclophotocoagulation and goniotomy were the most common procedures performed (33.0% and 21.9%, respectively).

CONCLUSIONS

A significant increase in MIGS use occurred over the recent 6-year period, despite limited evidence of their long-term safety or effectiveness, highlighting the need for trials comparing safety and outcomes of novel MIGS versus traditional surgical treatments for glaucoma.

Minimally Invasive Glaucoma Surgical Techniques for Open-Angle Glaucoma: An Overview of Cochrane Systematic Reviews and Network Meta-analysis

IMPORTANCE

Glaucoma affects more than 75 million people worldwide. Intraocular pressure (IOP)-lowering surgery is an important treatment for this disease. Interest in reducing surgical morbidity has led to the introduction of minimally invasive glaucoma surgeries (MIGS). Understanding the comparative effectiveness and safety of MIGS is necessary for clinicians and patients.

OBJECTIVE

To summarize data from randomized clinical trials of MIGS for open-angle glaucoma, which were evaluated in a suite of Cochrane reviews.

DATA SOURCES

The Cochrane Database of Systematic Reviews including studies published before June 1, 2021.

STUDY SELECTION

Reviews of randomized clinical trials comparing MIGS with cataract extraction alone, other MIGS, traditional glaucoma surgery, laser trabeculoplasty, or medical therapy.

DATA EXTRACTION AND SYNTHESIS

Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines by one investigator and confirmed by a second. Methodologic rigor was assessed using the AMSTAR 2 appraisal tool and random-effects network meta-analyses were conducted.

MAIN OUTCOMES AND MEASURES

The proportion of participants who did not need to use medication to reduce intraocular pressure (IOP) postsurgery (drop-free). Outcomes were analyzed at short-term (<6 months), medium-term (6-18 months), and long-term (>18 months) follow-up.

RESULTS

Six eligible Cochrane reviews were identified discussing trabecular bypass with iStent or Hydrus microstents, ab interno trabeculotomy with Trabectome, subconjunctival and supraciliary drainage devices, and endoscopic cyclophotocoagulation. Moderate certainty evidence indicated that adding a Hydrus safely improved the likelihood of drop-free glaucoma control at medium-term (relative risk [RR], 1.6; 95% CI, 1.4 to 1.8) and long-term (RR, 1.6; 95% CI, 1.4 to 1.9) follow-up and conferred 2.0-mm Hg (95% CI, -2.7 to -1.3 mm Hg) greater IOP reduction at long-term follow-up, compared with cataract surgery alone. Adding an iStent also safely improved drop-free disease control compared with cataract surgery alone (RR, 1.4; 95% CI, 1.2 to 1.6), but the short-term IOP-lowering effect of the iStent was not sustained. Addition of a CyPass microstent improved drop-free glaucoma control compared with cataract surgery alone (RR, 1.3; 95% CI, 1.1 to 1.5) but was associated with an increased risk of vraision loss. Network meta-analyses supported the direction and magnitude of these results.

CONCLUSIONS AND RELEVANCE

Based on data synthesized in Cochrane reviews, some MIGS may afford patients with glaucoma greater drop-free disease control than cataract surgery alone. Among the products currently available, randomized clinical trial data associate the Hydrus with greater drop-free glaucoma control and IOP lowering than the iStent; however, these effect sizes were small.

Reoperation for complications within 90 days of minimally invasive glaucoma surgery

OBJECTIVE

To describe reoperations that occurred within 90 days of minimally invasive glaucoma surgery (MIGS) at a single institution over a 30-month period.

SETTING

Tertiary care hospital.

DESIGN

Retrospective case series.

METHODS

Charts of adult patients who underwent trabecular microbypass stents, gel microstents, and goniotomy procedures (including gonioscopy-assisted transluminal trabeculotomy) from October 1, 2017, to March 15, 2020, at Wills Eye Hospital were examined. Outcome measures were unanticipated reoperations within the first 90 days after MIGS procedures and the complications that led to these reoperations.

RESULTS

A total of 448 MIGS procedures were performed on 436 eyes of 348 patients over a 30-month period by 6 glaucoma surgeons. Of these, 206 (46.0%) were trabecular microbypass stents (198 iStent/iStent inject and 8 Hydrus), 152 (33.9%) were gel microstents, and 90 (20.1%) were goniotomy procedures. Combined phacoemulsification took place in 256 eyes (58.7%). Reoperation within 90 days took place in 23 (5.3%) of 436 eyes, including 16 (10.5%) of 152 eyes in the gel microstent group, 4 (2.0%) of 198 eyes in iStent/iStent inject group, and 3 (3.3%) of 90 eyes in the goniotomy group. Indications for reoperation were elevated intraocular pressure (IOP) in 16 (69.6%) of 23 eyes, gel microstent tip exposure with wound leakage in 3 (13.0%) of 23 eyes, and early gel microstent encapsulation without elevated IOP in 1 (4.3%) of 23 eyes. Two (8.7%) of 23 eyes required reoperation for intraocular lens complications, whereas 1 (4.3%) of 23 eyes had elevated IOP and aphakia requiring reoperation.

CONCLUSIONS

The rate of reoperation within the first 90 days after MIGS was low. Elevated IOP and complications associated with gel microstents were the main indications for reoperation.

Microinvasive Glaucoma Surgery in US Ophthalmology Residency: Surgical Case Log Cross-sectional Analysis and Proposal for New Glaucoma Procedure Classification

PRECIS

A cross-sectional sample of the US ophthalmology residency graduating class of 2018 revealed that 18.4% of residents logged <5 traditional glaucoma surgeries, and 63.4% logged at least 1 microinvasive glaucoma surgery (MIGS).

PURPOSE

Describe the state of MIGS in US ophthalmology residency training and propose a glaucoma procedure classification system for residents' surgical case logs.

METHODS

Deidentified case logs from residents graduating in 2018 were requested from US residency program directors.

RESULTS

Case logs were received for 152/488 (31%) residents from 36/115 (31%) programs. The mean number of traditional glaucoma surgeries per resident was 9.0±5.9 (range: 0 to 31). The mean number of MIGS per resident was 5.2±8.9 cases (range: 0 to 58). There were 28/152 (18.4%) residents from 16/36 (44.4%) programs who logged <5 traditional glaucoma surgeries as primary surgeon, and 3/152 (2.0%) residents from 3/36 (8.3%) programs who logged zero traditional glaucoma surgeries as primary surgeon. There were 98/152 (64.5%) residents from 32/36 (88.8%) programs who logged <5 MIGS as primary surgeon, and 48/152 (31.6%) residents from 25 of 36 (69.4%) programs who logged zero MIGS as primary surgeon. There were 104/152 (63.4%) residents from 33/36 (91.6%) programs who logged at least 1 MIGS as primary surgeon; there were 3/36 (8.3%) residency programs where no resident logged any MIGS as primary surgeon.

CONCLUSIONS

US ophthalmology residents' MIGS experience varies widely. Residents can satisfy glaucoma surgery requirements with some MIGS, even in the absence of adequate traditional glaucoma surgeries. We propose a residency case log classification system that better reflects the growing role of MIGS in clinical practice and helps ophthalmic educators more accurately track procedures requiring related skills.

Survey of Microinvasive Glaucoma Surgery and Other Glaucoma Surgical Experience among United States Ophthalmology Residency Programs

Purpose  The aim of the study is to assess the state of glaucoma surgical training in United States ophthalmology residency programs, including experience with microinvasive glaucoma surgery (MIGS). Design  The design of the study is anonymous, internet-based national survey. Participants  Current United States ophthalmology residents of residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME). Methods  An anonymous survey link was emailed to all 120 accredited United States ophthalmology residency programs inviting residents to participate in an assessment of residency glaucoma surgical experience. Survey responses were collected between January 21, 2019 and March 4, 2019 and analyzed using descriptive statistics. Main Outcome Measures   The main outcomes of the study are demographic information, practice intentions, and anticipated primary surgical experience with ACGME-required glaucoma procedures and MIGS procedures, as self-reported by U.S. ophthalmology residents. Results  Of the estimated 1,479 U.S. ophthalmology residents, 161 residents participated (10.9%). A total of 118 residents (73.2%) reported any degree of anticipated MIGS primary surgical experience during residency, with the iStent being the most familiar technique. The likelihood of any anticipated MIGS experience during residency was not significantly different by geographic region ( p  = 0.16), however, anticipated volume varied significantly ( p  = 0.037). Of the 113 respondents who reported an intention to manage glaucoma surgically in their eventual practice, 25 (22.1%) reported no anticipated primary MIGS experience during residency. 73.3% of residents anticipating MIGS experience anticipated 0 to 10 cases, with 42.9% anticipating less than 5 cases as primary surgeon. Conclusion  MIGs are not a required component of the glaucoma surgical curriculum for U.S. ophthalmology residents. Although the majority of ophthalmology residents surveyed intend to manage glaucoma surgically in eventual practice, most receive minimal experience with these novel techniques during residency. Surgical training is variable by geographic region.

Safety and efficacy of microinvasive glaucoma surgery with cataract extraction in patients with normal-tension glaucoma

This study assesses the safety and efficacy of microinvasive glaucoma surgery (MIGS) with cataract extraction in patients with normal-tension glaucoma (NTG). In our sample of 45 NTG patients, mean intraocular pressure (IOP) decreased from 13.7 to 12.3 mmHg at 2.5 years, and mean medication burden decreased from 2.0 to 1.1 at 1.5 years. For success defined as IOP reduction ≥ 30% from baseline IOP with medication burden reduction from preoperative levels, success probability was 5.4% at 1.5 years. For success defined as medication burden reduction with an IOP reaching goal IOP as determined by the glaucoma specialist, success probabilities were 67.2% at 1.5 years and 29.4% at 2.5 years. At the last follow-up visit, eyes with two MIGS procedures with different mechanisms of action achieved successful medication reduction 68.8% of the time versus 35.7% achieved by a single MIGS procedure (p = 0.052). At their last visit, visual acuity was unchanged or improved in all eyes (100%). MIGS with cataract surgery results in modest reductions in IOP and medication burden in NTG patients, which may lead to lower costs and better therapeutic compliance. A combination of two MIGS procedures with different mechanisms of action may potentially be more effective in reducing medication burden than a single MIGS procedure in NTG patients. Further research is necessary to ascertain whether MIGS for NTG patients may help decrease medication burden while helping achieve goal IOP.

Canaloplasty with mitomycin C after previous combined cataract surgery and Schlemm's canal microstent implantation

We report on a 56-year-old male with primary open-angle glaucoma who underwent mitomycin C augmented canaloplasty enabling filtration in the right eye after cataract surgery combined with a Schlemm's canal microstent 3 years previously. He showed progressive glaucomatous optic neuropathy and was highly myopic (axial length 32.05 mm, spherical equivalent -18.75 dioptres in the right eye). Augmented canaloplasty was performed uneventfully and 360° catheterisation was achieved followed by the placement of a 10-0 polypropylene suture in Schlemm's canal. Intraocular pressure (IOP) in the first post-operative day was reduced from 19 to 6 mmHg. At 1-month follow-up IOP was 12 mmHg off glaucoma medications. The presence of a minimally invasive glaucoma surgery (MIGS) device did not hinder successful catheterisation of Schlemm's canal. Significant reduction of IOP was obtained in the early post-surgical period. No intra-operative complications were registered and only transient hyphema in early post-operative period was reported. This augmented canaloplasty could be an effective alternative to trabeculectomy even after Schlemm's canal microstent implantation.

Safety profile of minimally invasive glaucoma surgery

PURPOSE OF REVIEW

This article reviews the safety profile of trabecular meshwork/Schlemm's canal-based, subconjunctival, and suprachoroidal minimally invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Prospective randomized clinical trials and metaanalyses published during the 2019-2020 review period provided important data regarding the safety profile of trabecular meshwork/Schlemm's canal-based MIGS. Transient hyphema and intraocular pressure spikes are among the most common complications associated with this category of MIGS, but more serious adverse events such as cyclodialysis cleft formation may also occur. Trabecular bypass microstents and the intracanalicular scaffold are further subject to device-related complications, including malposition and obstruction. Recent case reports and retrospective case series have further characterized the safety profile of the subconjunctival gel stent, with adverse events ranging from self-limited hypotony to visually devastating endophthalmitis and suprachoroidal hemorrhage. Five-year results of the COMPASS XT study demonstrated significantly greater endothelial cell loss in patients randomized to receive CyPass Micro-Stent (Alcon Laboratories, Fort Worth, TX, USA) in combination with cataract surgery versus those who underwent cataract surgery alone, and ultimately led to a Food and Drug Administration Class I recall of the device.

SUMMARY

Trabecular meshwork/Schlemm's canal-based procedures are generally among the safest MIGS, with mostly self-limited and nonvision-threatening complications. Subconjunctival gel stent insertion is associated with both bleb-related and stent-specific adverse events, which are similar to those observed with trabeculectomy and tube shunt surgery, respectively. Removal of the CyPass Micro-Stent from the market underscores the need for high-quality, long-term safety data regarding MIGS.

Glaucoma in Adults-Screening, Diagnosis, and Management: A Review

IMPORTANCE

Glaucoma is the most common cause of irreversible blindness worldwide. Many patients with glaucoma are asymptomatic early in the disease course. Primary care clinicians should know which patients to refer to an eye care professional for a complete eye examination to check for signs of glaucoma and to determine what systemic conditions or medications can increase a patient's risk of glaucoma. Open-angle and narrow-angle forms of glaucoma are reviewed, including a description of the pathophysiology, risk factors, screening, disease monitoring, and treatment options.

OBSERVATIONS

Glaucoma is a chronic progressive optic neuropathy, characterized by damage to the optic nerve and retinal nerve fiber layer, that can lead to permanent loss of peripheral or central vision. Intraocular pressure is the only known modifiable risk factor. Other important risk factors include older age, nonwhite race, and a family history of glaucoma. Several systemic medical conditions and medications including corticosteroids, anticholinergics, certain antidepressants, and topiramate may predispose patients to glaucoma. There are 2 broad categories of glaucoma, open-angle and angle-closure glaucoma. Diagnostic testing to assess for glaucoma and to monitor for disease progression includes measurement of intraocular pressure, perimetry, and optical coherence tomography. Treatment of glaucoma involves lowering intraocular pressure. This can be achieved with various classes of glaucoma medications as well as laser and incisional surgical procedures.

CONCLUSIONS AND RELEVANCE

Vision loss from glaucoma can be minimized by recognizing systemic conditions and medications that increase a patient's risk of glaucoma and referring high-risk patients for a complete ophthalmologic examination. Clinicians should ensure that patients remain adherent with taking glaucoma medications and should monitor for adverse events from medical or surgical interventions used to treat glaucoma.

Personalising surgical treatments for glaucoma patients

Surgical treatments for glaucoma have relied for decades on traditional filtering surgery such as trabeculectomy and, in more challenging cases, tubes. Antifibrotics were introduced to improve surgical success in patients at increased risk of failure but have been shown to be linked to a greater incidence of complications, some being potentially vision-threatening. As our understanding of glaucoma and its early diagnosis have improved, a more individualised management has been suggested. Recently the term "precision medicine" has emerged as a new concept of an individualised approach to disease management incorporating a wide range of individual data in the choice of therapeutic modalities. For glaucoma surgery, this involves evaluation of the right timing, individual risk factors, targeting the correct anatomical and functional outflow pathways and appropriate prevention of scarring. As a consequence, there is an obvious need for better knowledge of anatomical and functional pathways and for more individualised surgical approaches with new, less invasive and safer techniques allowing for earlier intervention. With the recent advent of minimally invasive glaucoma surgery (MIGS) a large number of novel devices have been introduced targeting potential new sites of the outflow pathway for lowering intraocular pressure (IOP). Their popularity is growing in view of the relative surgical simplicity and apparent lack of serious side effects. However, these new surgical techniques are still in an era of early experiences, short follow-up and lack of evidence of their superiority in safety and cost-effectiveness over the traditional methods. Each year several new devices are introduced while others are withdrawn from the market. Glaucoma continues to be the primary cause of irreversible blindness worldwide and access to safe and efficacious treatment is a serious problem, particularly in the emerging world where the burden of glaucoma-related blindness is important and concerning. Early diagnosis, individualised treatment and, very importantly, safe surgical management should be the hallmarks of glaucoma treatment. However, there is still need for a better understanding of the disease, its onset and progression, the functional and structural elements of the outflow pathways in relation to the new devices as well as their long-term IOP-lowering efficacy and safety. This review discusses current knowledge and the future need for personalised glaucoma surgery.